PHYSIOLOGY OF THE RED MANGROVE. 



Hydrometric Readings in Bisgayne Bay and Miami River. 

 August I to S Inclusive. 



Temperature Specific 



(Centigrade). Gravity. 



Atlantic Ocean, nine-foot depths *28.3° *i.oi50 



28.0° 1. 0120 



Off shore 28.3° 1.0120 



28.0° 1.0130 



Half way across Biscayne Bay 28.1° 1.0105 



28.0° 1. 0105 



Mouth of Miami River 28.0° 1.0015 



27.6° 1.0080 



Half mile up stream 27.5° 0.9975 



27.0° 1. 0100 



One mile up stream 27.2° 0.9980 



27.0° 1. 0000 



One and one half miles up stream 26.7° 0.9980 



27.0° 1. 0000 



Tv\o miles up stream 26.5° 0.9977 



26.4° 0.9982 



Two and one half miles up stream 26.1° 0.9980 



26.1° 0.9985 



Biscayne Bay, seven-foot depths 28.0° 1.0090 



28.0° I.OIIO 



Arch Creek mouth 28.2° i.ooio 



27.8° 1.0045 



Arch Creek, one mile up stream 27.7° i.oooo 



28.0° 1.0050 



Arch Creek, two miles up stream 29.5° 0.9975 



29.0° 1.0050 



663 



mode of branching and trunk formation is the chief difference here. 

 While the difference in the forms of the two " forms" has not been 

 pronounced enough to engage the attention of systematists and 

 taxonomists it is a very interesting field for genetical investigation, 

 since Guppy suggests that the " selala " type might be a hybrid be- 

 tween R. mucronata and R. mangle, or perhaps there is a persistent 

 dimorphism in R. mucronata. In conclusion the writer may say 

 that only the " mangle chico " type of R. mangle is found in Florida 

 and the keys, just as Guppy has found it to be the only type present 

 in Jamaica and the West Indies. 



* The upper readings of each pair represents that at the surface of the 

 river, while the lower readings were those taken on the bottom samples. 



